verview of BR 11 Structure and Function (These are just some of the many themes we have talked about this semester) Water 1. ohesion/surface tension 2. Temperature moderation 3. Solvent Ability ydrophilicity dissolves polar things & ions ydrophobicity herds away nonpolar things 4. Ionization ability (p) Figure on p. 53 of water dissociating Figure 3.8 Increasingly Acidic [ ] > [ ] eutral [ ] = [ ] Increasingly Basic [ ] < [ ] Various forms of arbon molecules and functional groups = = ydronium ion ( 3 ) ydroxide ion ( ) 1
Amino Acids and Proteins Lipids arbohydrates monomers and polymers Membrane Functions 1. boundaries 2. Localize specific functions 3. transport 6. ell-cell adhesion 5. ell-cell communication 4. Signal detection A. Transport channels and pumps B. Links to structural proteins. Receptors - doorbells D. Enzymes localized biochemical rxns E. Energy Generation utilize gradient Proton pump Sucrose- cotransporter Diffusion of Sucrose Voltage Ligand Mechanosensitive 2
endoplasmic reticulum EDPLASMI RETIULUM (ER) Rough ER Smooth ER Animal ell ULEUS nucleus Bacterial and Viruses entrosome cytosol Plasma membrane YTSKELET Microfilaments Intermediate filaments Microtubules Ribosomes ribosomes Peroxisome Figure 6.9 Mitochondrion mitochondrion Lysosome lysosome Golgi apparatus In animal cells but not plant cells: Lysosomes entrioles Flagella (in some plant sperm) Storage and Transfer of Energy Enzymes bring substrates together to lower the activation energy of a reaction ΔG = Δ - TΔS e 8.14 Free energy A B D Transition state A B E A D Reactants A B G < D Products Progress of the reaction - 3
Proton gradients power reactions to create high energy Fatty Acid xidation (β (β-oxidation) Priming Step 2 Saturated hydrocarbon 2 LIGT ADP ADP LIGT REATR ALVI YLE 2e2 removed ADP ADP and can be used to transfer energy STRMA (Low concentration) 2 [2 ] (sugar) ytochrome Photosystem II complex Photosystem I Light 2 ADP reductase Fd 3 ADP 2 ADP Pq Pc 2 2 TYLAKID SPAE 1 (igh concentration) 1 2 2 2 2 Energy is captured in many small steps in this metabolic pathway To alvin cycle Thylakoid STRMA membrane (Low concentration) synthase ADP P Figure 10.17 -captures Reducing potential AD FAD2 2e- unsaturated hydrocarbon Ketone alcohol 2 removed Signaling, Information transfer, and feedback loops Ester (acid) Information stored in DA is used to build proteins DA mra DA TRASRIPTI 1 RA is transcribed from a DA template. RA transcript RA PRESSIG 2 In eukaryotes, the RA transcript (premra) is spliced and modified to produce mra, which moves from the nucleus to the cytoplasm. ly-a Po RA polymerase DA -> mra -> Protein Exon RA transcript (pre-mra) Intron Aminoacyl-tRA synthetase p a ULEUS Amino acid tra FRMATI F IITIATI MPLEX YTPLASM 3 After leaving the nucleus, mra attaches to the ribosome. AMI AID ATIVATI 4 Each amino acid attaches to its proper tra with the help of a specific enzyme and. Growing polypeptide mra A lypo Activated amino acid Ribosomal subunits polypeptide p a A lypo TRASLATI A E U A A AAA UG G UU UA UG odon Ribosome Anticodon 5 A succession of tras add their amino acids to the polypeptide chain as the mra is moved through the ribosome one codon at a time. (When completed, the polypeptide is released from the ribosome.) 4
Sugar-phosphate backbone end P 2 4 P 2 P 2 1 2 P 2 1 4 Phosphate 2 Sugar (deoxyribose) end DA structure itrogenous bases 3 Thymine (T) G T A Adenine (A) 1 nm G 3.4 nm G G ytosine () T A T A DA nucleotide G 0.34 nm Guanine (G) Ribosomes translate the RA message into a polypeptide mra Amino end Growing polypeptide odons Second mra base U A G UUU UU UAU UGU U Phe Tyr ys UU U UA UG U UUA UA Ser UAAStop UGAStop A UUG Leu UG UAGStop UGGTrp G UU U AU GU U is U A G UA Leu A Pro Arg AA GA A Gln UG G tra AG GG G AUU AU AAU AGU U Asn AU lle A AA A AG Ser Thr AUA AA AAA AGA A Met or Lys AUG AG AAG AGG Arg G start GUU GU GAU GGU U G GU G GA Asp GG Val Ala Gly GUA GA GAA GGA A Glu GUG GG GAG GGG G First mra base ( end) Third mra base ( end) Mitosis produces an exact copy of the parent cell. Used for growth and asexual reproduction. ot paired Mitosis vs Meiosis diploid Meiosis produces reduced (haploid) gametes, which are genetically unique. ecessary for sexual reproduction. Meiosis generates variation through: - independent assortment of chromosomes - crossing over omologs pair in meiosis 1 haploid Sister chromatids separate in meiosis 2 5
DA replication machine DA is always synthesized 5 to 3 Information must be copied exactly eqch time a cell divides PR is just repeated cycles of DA synthesis in a test tube DA sequences are determined by poisoning a synthesis reaction with dideoxy nuclotides 1º messenger Effector Enzymes Target Enzymes ells detect signal & respond 2º messengers Signal transduction pathways AMPLIFY the signal 6
Regulatory gene DA mra Protein The trp operon: regulated synthesis of repressible enzymes trpr Figure 18.21a RA polymerase Promoter perator trp operon Genes of operon trpe trpd trp trpb trpa mra E D B A Polypeptides that make up enzymes for tryptophan synthesis Tryptophan absent -> repressor inactive -> operon on ell typespecific transcription All cells have the same genes, but only certain genes are expressed in each tissue Liver cell Fig 19.7 ontrol elements Enhancer Liver cell nucleus Albumin gene expressed rystallin gene not expressed Promoter Albumin gene rystallin gene Lens cell nucleus Albumin gene not expressed rystallin gene expressed Different set of activator proteins in the two cell types Lens cell ell ycle Regulators and ancer Thank you! 7